1. Field of the Invention
The present invention relates to a plasma jet generating apparatus.
In a plasma jet generating apparatus, an electric arc is formed between an electrode and a nozzle electrode. The thus formed electric-arc is then confined inside the nozzle with the aid of working gas under a thermal pinch effect for discharge of a high temperature plasma jet from the nozzle.
Very high energy can be concentrated in the plasma jet, in the form of temperatures as high as 10.sup.4 K and flow rates as high as 10.sup.3 m/s Thus, plasma jets can be widely applied for industry, engineering, and the like. At the present, plasma jets are being used in industry for fusion cutting or welding of stainless steels, alloys, and the like, spraying of metals and ceramics, melting and refining of pure metals and alloys, high temperature chemical reactions of polymers, and so on.
2. Description of the Related Art
Plasma jets provide very high efficiency in supplying heat energy. Accordingly, it is expected that higher power plasma jets will come into strong demand in the near future.
However, prior art plasma jet generating apparatuses have hithertofore been low in power, such as less than 100 kW. If one tries to use such low power apparatuses for high power plasma jets, the problem arises of rapid damage or consumption of the electrodes. This is believed to be due to the large-current, low-voltage driving nature of the prior art plasma jet generating apparatus. Anyway, it is very difficult to generate a high power plasma jet with the prior art apparatus.